Crossed and uncrossed network cable?

Dolby

Dolby

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What's the difference between these cables?
Can a cable influence speed? If I have 10/100 devices on either side, is there a chance the cable could somehow reduce speed?
Does lenth reduce speed?
 
http://en.wikipedia.org/wiki/Crossover_cable

the cable does not really influence speed.

well, except if you plug a cable that only supports 100mb/s into a gigabit card, you will obviously only get 100mb/s.

And as far as length, in my experience, no.

But that said, if the cable is dodgy, like say one of the cables inside is broken or does not make proper contact, then the connection will obviously be dodgy. I have seen that they then report their connection speed as 10mb/s.
 
that link does not really explain much, but you would basically use a crossover cable to directly connect 2 pc's without a switch or hub in between.
 
And from what I understand as well, crossed cables can be used IN a switch/hub environment too - but uncrossed cannot be used for straight. So I'd guess most cables around are crossed - in fact I see little reason for uncrossed?
 
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About the length question... CAT5 cable starts losing it at about 250m but can be used up to 300m in a suitable environment. If you need to install a 1km ethernet cable, don't! or use repeaters :p
 
Ok ... we can cross off length as it's DEFINATLEY not the length that appears to giving me lower speeds ;)
 
yes, there is hardly a need for crossover cables these days, most NIC's are auto switchable (or whatever).

only reason I still use them is because all my firewalls are built on old PI to PIII hardware and older network cards, so I use them to connect firewalls to servers or pc's etc.
 
Take a closer look at the cable. Obviously there could be a bend in the cable that could have damaged the cores. But more often than not its either the rj45 male plugs that have been poorly crimped ("dry" connections), or there are too few twists per inch (e.g being wound up incorrectely, untwisting the cores) in the length of the cable or at the ends.
 
Oh, and make sure the hard drives (if applicable) in the systems arent slow as a tortoise going up hill.
 
Use another cable to test, that way you will eliminate the cable if nothing changes.

Just to answer your first question.

With a straight cable, the send at one end goes to the send on the other end, and the recieve on one end goes to the recieve on the other end.

With crossover, the send on the one end goes to the recieve on the other end, and so on.

Dolby said:
"... but uncrossed cannot be used for straight. ...
Click to expand...

An uncrossed cable is a straight cable, and is used as the industry standard.


.
 
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